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30
Severe       Slight to moderate
25       reduction         reduction

20

15
No reduction in
10
infiltration rate
5

0
0         1        2        3      4        5    6
Salinity of Applied Water (dS/m)
Interaction of total salinity as EC with the sodium adsorption ratio of applied
water for causing potential infiltration problems.
(Ayers, R.S. and D.W. Westcott. 1985. Water quality for agriculture. United Nations
FAO Irrig & Drainage Paper No. 29.)
CONVERSION CALCULATIONS FOR SOIL EXTRACT AND WATER QUALITY EVALUATION

Total Salts                                          pH       Ca       Mg       Na               HCO3      SO4        Cl        F       NO3        B
Sample Site TDS (ppm, mg/l)                                                 mg/l     mg/l     mg/l             mg/l      mg/l      mg/l      mg/l     mg/l      mg/l
Example         3120                                                 7.6    347        91     482               210      1410       450        0.3      13        4.5
Enter Your
Samples Here

EC                                          pH        Ca       Mg      Na            HCO3         SO4       Cl         F       NO3        B
Sample Site           dS/m                                                  meq/l    meq/l   meq/l   SAR    meq/l        meq/l    meq/l      mg/l     mg/l      mg/l
Example               4.9                                            7.6     17.4     3.8     21.0     6.4   3.4         14.7     12.9         0.3      13        4.5
Results for            0.0                                            0.0      0.0     0.0      0.0 #DIV/0!   0.0          0.0       0.0          0        0         0
Your Samples            0.0                                            0.0      0.0     0.0      0.0 #DIV/0!   0.0          0.0       0.0          0        0         0

DEFINITIONS / CONVERSIONS
NOTE: It is necessary to convert such units as TDS (total dissolved solids in mg/l) and mg/l (milligram/liter of water, which is the
same as ppm, parts per million) into meq/l (milliequivalents/liter) so that concentrations of the different salts can be compared for their
"equivalent" chemical activity on soil structure and plant uptake.
EC               dS/m                                    Electical Conductivity ~= TDS / 640 (Not as accurate for EC > 4.)
pH                                                       pH = -Log(H+) in solution. pH 7.6 = 10-7.6 moles of hydrogen / liter.
Ca               meq/l                                   Calcium = mg/l / 20
Mg               meq/l                                   Magnesium = mg/l / 24
Na               meq/l                                   Sodium = mg/l / 23 (Westside pistachios okay to 30-40 meq/l. Unpublished UCCE data.)
SAR
Na         The Sodium Adsorption Ratio is a measure of the potential of a water to
SAR                    cause soil structural/infiltration problems due to sodium dispersion of soil
Ca  Mg      aggregates. However, more Na can be tolerated as the EC of the water
2         increases. The goal is to keep SAR < 5 * EC. (See attached chart by
Ayers and Westcott.)
HCO3               meq/l                                   Bicarbonate = mg/l / 61
SO4               meq/l                                   Sulfate = mg/l / 96
Cl               meq/l                                   Chloride = mg/l / 35 (Westside pistachios okay to 30-40 meq/l. UnpublishedUCCE data.)
F                mg/l                                    Fluoride (not common for most ag water suitability analyses.
NO3                mg/l                                        Nitrate: 45 mg/l or ppm is max drinking water standard. NO3 * 0.612 = N fertilizer equiv.

B                mg/l                                        Boron: below 0.75 best for all crops. Up to 5 okay for most field crops and pistachios. Some

35

30
Severe             Slight to moderate
25       reduction                  reduction

20

15                                                                 Example Water
No reduction in No infiltration problem.
10
infiltration rate
5

0
0             1        2        3      4        5                       6
Salinity of Applied Water (dS/m)
Interaction of total salinity as EC with the sodium adsorption ratio of applied water for
causing potential infiltration problems.
(Ayers, R.S. and D.W. Westcott. 1985. Water quality for agriculture. United Nations FAO
Irrig & Drainage Paper No. 29.)
35

Severe       Slight to moderate
25       reduction         reduction

20

15
No reduction in
10
infiltration rate
5

0
0         1        2        3      4        5   6
Salinity of Applied Water (dS/m)
is a measure of the potential of a water to
e soil structural/infiltration problems due to sodium dispersion of soil

t to moderate
duction

No reduction in
infiltration rate

3      4        5                      6
plied Water (dS/m)
CALCULATING LEACHING DEPTH TO ACHIEVE DESIRED
SALINITY FOR SOIL RECLAMATION
(Using fresh water with EC <= 1 mmho/cm)

CALCULATING SAR, ESP AND DESIRED LEACHING DEPTH
Data Required from Soil Extract Analysis
EXAMPLE       (%)               (dS/m)            (meq/l)                                   Desired Dsrd/Orig
Depth        SP         pH       EC       Ca       Mg         Na     SAR    ESP   EC/ESP   Salinity     EC
0-1'        40        7.9      5.5      34.2      4.6        21.7    4.9   5.7    1.0        3        0.55
1-2'        45        8.0      6.7      29.9     4.3   39.6   9.6 11.4    1.7        3      0.45
2-3'        45        8.0      7.3      25.1      4    51.8  13.6 15.8    2.2        3      0.41
TOTAL DEPTH OF LEACHING (feet of water) FOR 3 FEET:

CALCULATING SAR, ESP AND DESIRED LEACHING DEPTH
Data Required from Soil Extract Analysis
Your Nos.     (%)               (dS/m)            (meq/l)                                   Desired Dsrd/Orig
Depth        SP         pH       EC       Ca       Mg         Na     SAR    ESP   EC/ESP   Salinity     EC
0-1'                                                                ##### ##### #DIV/0!              #DIV/0!
1-2'                                                        ##### ##### #DIV/0!            #DIV/0!
2-3'                                                        ##### ##### #DIV/0!            #DIV/0!
TOTAL DEPTH OF LEACHING (feet of water) FOR 3 FEET:
Note: Samples do not have to be from an exact depth of 1 foot increments. However, the calculated depth of
required leaching assumes a 1 foot depth of soil. If your sample depth was 1.5 feet (18 inches) then simply multiply
the required depth by 1.5 to get the correct leaching requirement.

Always want EC/ESP < 5 to avoid serious infiltration problems.
To calculate SAR:                    SAR = Na / SqRt(Ca+ Mg/2)
To calculate ESP from SAR: ESP = 100*(0.01475*SAR - 0.0126)/(1+ (0.01475*SAR - 0.0126))

Required Leaching (ft water/ft depth soil) = K / (Desired EC/Original EC) - K
(K factor of 0.3 for continuous ponding.)
(K factor of 0.15 for sprinkling or drip.)
Hoffman, G.J. 1996. “Leaching fraction and root zone salinity control.” Agricultural Salinity
Assessment and Management. ASCE. New York, N.Y. Manual No. 7:237-247
Sprinkling/Drip
Reqd Depth
to Leach
(ft water/ft soil)
0.13
0.19
0.22
0.53

Sprinkling/Drip
Reqd Depth
to Leach
(ft water/ft soil)
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
calculated depth of
hes) then simply multiply

ginal EC) - K
Table 3 CONCENTRATION FACTORS (X) FOR PREDICTING SOIL SALINITY (ECe)1 FROM
IRRIGATION WATER SALINITY (ECw) AND THE LEACHING FRACTION (LF)
Applied
Water
Needed
Concentra                                     3.5
Leaching                   tion
Fraction (Percen Factor 2                  3
(LF)      t of ET)

Concentration Factor for ECe
(X)
0.05      105%          3.2           2.5
y = 0.5057x-0.611
0.1      111%          2.1
2
0.15      118%          1.6
0.2      125%          1.3           1.5
0.25      133%          1.2
1
0.3      143%           1
0.4      167%          0.9           0.5
0.5      200%          0.8
0.6      250%          0.7             0
0.7      333%          0.6                0         0.2        0.4          0.6        0.8        1
Leaching Fraction
0.8      500%          0.6
1
The equation for predicting the soil salinity expected after several years of irrigation with water
of salinity ECw is: ECe (dS/m) = ECw (dS/m).X
. Ayers, R.S., D.W. Westcot. Water Quality for Agriculture. FAO Irrigation and Drainage Paper 29 Rev.
1, Reprinted 1989, 1994 . http://www.fao.org/DOCREP/003/T0234E/T0234E00.htm
(This publication is one of the most extensive references on water quality and can be

Average rootzone saturation extract EC (dS/m) after long-term irrigation with a
given salinity of water (ignoring precipitation/dis-solution reactions in the soil)
and Leaching Fraction.
Irrigation
Water EC Leaching Fraction (LF) above crop ET requirement
(dS/m)   0.05     0.1      0.15      0.2     0.3                        0.4       0.5
0.1
0.4  1.26
0.7  2.21   1.45
1  3.15   2.06       1.61
1.3  4.10   2.68       2.10     1.76
1.6  5.05   3.30       2.58     2.16    1.69
1.9  5.99   3.92       3.06     2.57    2.01                       1.68
2.2  6.94   4.54       3.55     2.97    2.32                       1.95     1.70
2.5  7.88   5.16       4.03     3.38    2.64                       2.21     1.93
2.8  8.83   5.78       4.51     3.79    2.95                       2.48     2.16
3.1  9.78   6.40       5.00     4.19    3.27                       2.74     2.39
3.4 10.72   7.02       5.48     4.60    3.59                       3.01     2.63
3.7 11.67   7.64       5.96     5.00    3.90                       3.28     2.86
4 12.61   8.26       6.45     5.41    4.22                       3.54     3.09
4.3 13.56   8.88       6.93     5.81    4.54                       3.81     3.32
4.6 14.51   9.50       7.41     6.22    4.85                       4.07     3.55
4.9 15.45  10.12       7.90     6.62    5.17                       4.34     3.78                  Average rootzo
SOLVING FOR DESIRED LEACHING FRACTION DIRECTLY:                                                             term irrigation
Regressing the rootzone salinity concentration factors in FAO29 and rearranging to                          precipitation/d
solve for Leaching Fraction (LF):                                                                           Leaching Frac
LF = 0.326 (Desired ECe/ECirr)^ -1.64                                                     Irrigation Lea
Water EC req
(dS/m)
Table 3 CONCENTRATION FACTORS (X) FOR PREDICTING SOIL SALINITY (ECe)1 FROM IRRIGATION
WATER SALINITY (ECw) AND THE LEACHING FRACTION (LF)
Applied
Water       Concen
3.5
Leaching        Needed       -tration
Fraction (Percent of Factor                      3
(LF)            ET)          (X)
Concentration Factor for ECe

0.05           105%          3.2             2.5
y = 0.5057x-0.611
0.1           111%          2.1
2
0.15           118%          1.6
0.2           125%          1.3             1.5
0.25           133%          1.2
1
0.3           143%           1
0.4           167%          0.9             0.5
0.5           200%          0.8
0.6           250%          0.7               0
0.7           333%          0.6                 0        0.2         0.4         0.6         0.8      1
Leaching Fraction
0.8           500%          0.6
1
The equation for predicting the soil salinity, ECe, expected after several years of irrigation with
water of salinity ECw is: ECe (dS/m) = ECw*(Concentration Factor, X)
. Ayers, R.S., D.W. Westcot. Water Quality for Agriculture. FAO Irrigation and Drainage Paper 29 Rev. 1,
Reprinted 1989, 1994 . http://www.fao.org/DOCREP/003/T0234E/T0234E00.htm
(This publication is one of the most extensive references on water quality and can be downloaded for
free at the above website.)
Water Quality for Agriculture. R.S. Ayers, D.W. Westcot. FAO Irrigation and Drainage
Paper 29 Rev. 1, Reprinted 1989, 1994 http://www.fao.org/DOCREP/003/T0234E/T0234E00.htm

2.4.2 Salinity Control by Leaching

When the build-up of soluble salts in the soil becomes or is expected to become excessive, the salts
can be leached by applying more water than that needed by the crop during the growing season. This
extra water moves at least a portion of the salts below the root zone by deep percolation (leaching).
Leaching is the key factor in controlling soluble salts brought in by the irrigation water. Over time, salt
removal by leaching must equal or exceed the salt additions from the applied water or salts will build
up and eventually reach damaging concentrations. The questions that arise are how much water should
be used for leaching and when should leachings be applied?

i. The leaching requirement1

To estimate the leaching requirement, both the irrigation water salinity (ECw) and the crop tolerance
to soil salinity (ECe) must be known. The water salinity can be obtained from laboratory analysis
while the ECe should be estimated from appropriate crop tolerance data given in the tables in Section
2.4.3 of this paper. These tables give an acceptable ECe value for each crop appropriate to the
tolerable degree of yield loss (usually 10 percent or less).

The necessary leaching requirement (LR) can be estimated from Figure 7 for general crop rotations.
For more exact estimates for a particular crop, the leaching requirement equation (9) (Rhoades 1974;
and Rhoades and Merrill 1976) should be used:

where:            =   the minimum leaching requirement needed to control salts within the tolerance
LR
(ECe) of the crop with ordinary surface methods of irrigation
ECw     =   salinity of the applied irrigation water in dS/m
ECe     =   average soil salinity tolerated by the crop as measured on a soil saturation
extract. Obtain the ECe value for the given crop and the appropriate acceptable
yield from Table 4. It is recommended that the ECe value that can be expected to
result in at least a 90 percent or greater yield be used in the calculation. (Figure 7
was developed using ECe values for the 100 percent yield potential.) For water in
the moderate to high salinity range (>1.5 dS/m), it might be better to use the ECe
value for maximum yield potential (100 percent) since salinity control is critical
to obtaining good yields.

The total annual depth of water that needs to be applied to meet both the crop demand and leaching
requirement can be estimated from equation (7).

where:    AW      =   depth of applied water (mm/year)
ET      =   total annual crop water demand (mm/year)
LR      =   leaching requirement expressed as a fraction
(leaching fraction)
The total annual depth of water that needs to be applied to meet both the crop demand and leaching
requirement can be estimated from equation (7).

where:     AW     =   depth of applied water (mm/year)
ET     =   total annual crop water demand (mm/year)
LR     =   leaching requirement expressed as a fraction
(leaching fraction)

1
In many texts, the Terms ‘leaching fraction (LF)’ and ‘leaching requirement (LR)’ are used
interchangeably. They both refer to that portion of the irrigation which should pass through the root
zone to control salts at a specific level. While LF indicates that the value be expressed as a fraction,
LR can be expressed either as a fraction or percentage of irrigation water.

Fig. 7 Effect of applied water salinity (ECw) upon root zone soil salinity (ECe) at various leaching
fractions (LF)

ii. Timing of leachings

It takes time to accumulate salts in the root zone to a concentration that reduces yield. Most irrigation
water is of such good quality that, without leaching, two or more years of irrigation will be required
before salinity accumulates sufficiently to affect yield. Further, the later in the growing season the salts
reach damaging concentrations, the less will be their effect. This suggests that if salts are low enough
at the start of the irrigation season, efficiency of water use during the growing season can be 100
percent (no leaching) without loss of yield due to salinity. For the next season, rainfall, dormant season
and pre-plant irrigations, singly or in combination, can be used to replenish deep soil moisture and
leach soils free enough of accumulated salts to allow efficient water use again during the next growing
season. It is often difficult to supply both essential crop water and leaching water during the hot
ii. Timing of leachings

It takes time to accumulate salts in the root zone to a concentration that reduces yield. Most irrigation
water is of such good quality that, without leaching, two or more years of irrigation will be required
before salinity accumulates sufficiently to affect yield. Further, the later in the growing season the salts
reach damaging concentrations, the less will be their effect. This suggests that if salts are low enough
at the start of the irrigation season, efficiency of water use during the growing season can be 100
percent (no leaching) without loss of yield due to salinity. For the next season, rainfall, dormant season
and pre-plant irrigations, singly or in combination, can be used to replenish deep soil moisture and
leach soils free enough of accumulated salts to allow efficient water use again during the next growing
season. It is often difficult to supply both essential crop water and leaching water during the hot
summer season. The key factor to remember is that leaching is not needed until accumulating salinity
is expected to exceed crop tolerance and reduce yield.

The timing of leachings does not appear to be critical provided crop tolerance is not exceeded for
extended or critical periods of time. This certainly does not mean that leaching is relatively
unimportant. The leaching requirement must be satisfied to prevent excessive salt accumulation.
Leaching can be done at each irrigation, each alternate irrigation or less frequently, such as seasonally
or at even longer intervals, as necessary to keep salinity below the threshold above which yields may
be unacceptably reduced. In many instances, the usual inefficiencies of water application satisfy the
leaching requirement and additional leaching is wasteful of water (see Example 3). Where low
leaching fractions (<0.10) are needed, as with good quality water, inefficiencies in irrigation water
application will almost always apply sufficient extra water to accomplish leaching. In other instances,
particularly with higher salinity water, meeting the leaching requirement is difficult and requires large
amounts of water, possibly adding to a drainage problem. It can be assumed that an appreciable
portion of the total deep percolation losses from normal irrigation practices is useful in controlling
salinity.

EXAMPLE 3 - LEACHING REQUIREMENT CALCULATION

A maize crop is irrigated by furrow irrigation. The crop is planted in a uniform loam soil and river
water, which has an ECw = 1.2 dS/m, is used for irrigation. The crop evapotranspiration (ET) is 800
mm/season. The irrigation application efficiency is 0.65. Therefore the total amount of water that must
be applied to meet crop ET demand is 800 mm/0.65 = 1230 mm/season. How much additional water
must be applied for leaching?

Given:          ECw = 1.2 dS/m
ECe = 2.5 dS/m (from Table 4 for maize at a 90 percent yield potential)
ECe = 1.7 dS/m (from Table 4 for maize at a 100 percent yield potential)

Explanation: The leaching requirement can be calculated using equation (9) and substituting the
appropriate ECe value for the desired yield potential (from Table 4).

The actual amount of water to be applied to supply both crop ET and leaching (long-term salt
control) can be found by using equation (7).
The actual amount of water to be applied to supply both crop ET and leaching (long-term salt
control) can be found by using equation (7).
ation and Drainage
E/T0234E00.htm

e excessive, the salts
e growing season. This
ercolation (leaching).
on water. Over time, salt
water or salts will build
how much water should

and the crop tolerance
laboratory analysis
in the tables in Section
propriate to the

eneral crop rotations.

s within the tolerance
tion

a soil saturation
appropriate acceptable
e that can be expected to
he calculation. (Figure 7
d potential.) For water in
be better to use the ECe
linity control is critical

demand and leaching
demand and leaching

(LR)’ are used
pass through the root
pressed as a fraction,

at various leaching

s yield. Most irrigation
ation will be required
growing season the salts
if salts are low enough
season can be 100
rainfall, dormant season
ep soil moisture and
during the next growing
ter during the hot
s yield. Most irrigation
ation will be required
growing season the salts
if salts are low enough
season can be 100
rainfall, dormant season
ep soil moisture and
during the next growing
ter during the hot
l accumulating salinity

is not exceeded for
is relatively
salt accumulation.
ntly, such as seasonally
bove which yields may
application satisfy the
e 3). Where low
es in irrigation water
hing. In other instances,
ficult and requires large
at an appreciable
useful in controlling

m loam soil and river
nspiration (ET) is 800
mount of water that must

potential)
d potential)

d substituting the
4).

and leaching (long-term salt
and leaching (long-term salt
WATER ANALYSIS 23 SEPT, 2003 (Order as received)
EC        Ca        Mg        Na                  Sum            HCO3-   CO3-2   C1-1     SO 4-2    Sum
Well        pH                                             K meq/l              SAR
dS/m      meq/l     meq/l     meq/l               Cations         meq/l   meq/l   meq/l    meq/l    Anions
BAR/P-1      7.14      1.73       7.6       8.4      5.6       0.1       21.7     2.0    7.1     0.6     8.5       2.3     18.5
BAR/P-H       7.44      1.81       8.4       9.8      7.0       0.0       25.3     2.3    6.0     0.8     8.4       4.4     19.6
BAR/R-E       7.52      1.76       7.1       9.7      7.1       0.1       23.9     2.5    6.8     0.8     9.3       3.0     19.8
BV/R-G       7.44      0.50      1.75       1.6      1.3       0.2        4.9     1.1    2.4     0.2     1.4       0.1      4.1
TS/C       8.38      0.38       1.2       1.3      1.0       0.1        3.6     0.9    1.6     0.2     1.1       0.1      3.0
TS/R-Z       7.28      0.16      0.35       0.5      0.5       0.1        1.4     0.8    0.4     0.2     0.5       0.1      1.1
MS/P        7.74      0.85       3.1       5.5      1.8       0.0       10.5     0.9    5.6     0.6     1.4       0.1      7.6
MS/R-G       7.95      0.40       1.3       1.9      1.0       0.1        4.3     0.8    1.6     0.2     1.2       0.5      3.4
VILL/R-P      7.27      1.57       4.3       7.2      7.5       0.4       19.3     3.2    7.5     0.8     7.4       1.1     16.9
VILL/P-N      7.58      2.22       7.8       8.3      7.8       0.0       23.9     2.8    5.2     0.8     10.2      3.3     19.4

SORT BY    HCO3-                                                                                                                               1
Acid to
EC        Ca        Mg        Na               Sum               HCO3-   CO3-2   C1-1     SO 4-2    Sum      HCO3-      neutrlz
Well        pH                                             K meq/l              SAR
dS/m      meq/l     meq/l     meq/l            Cations            meq/l   meq/l   meq/l    meq/l    Anions   (%Anion)   (lb/ac-ft)     2.2026 lb/kg
1     VILL/P-N   7.58    2.22        7.8       8.3         7.8       0.0      23.9     2.8    5.2     0.8     10.2      3.3     19.4      27%          900        3.79 l/gal   1234.891 m3/ac-ft
2     BAR/P-H    7.44    1.81        8.4       9.8         7.0       0.0      25.3     2.3    6.0     0.8      8.4      4.4     19.6      30%          1004
3     BAR/R-E    7.52    1.76        7.1       9.7         7.1       0.1      23.9     2.5    6.8     0.8      9.3      3.0     19.8      34%          1111     133lb/ac-ft = 0.048893 kg acid/m3
4      TS/R-Z    7.28    0.16       0.35       0.5         0.5       0.1       1.4     0.8    0.4     0.2      0.5      0.1      1.1      34%          106                    to neutralize 1 meq/l HCO3
5     BAR/P-1    7.14    1.73        7.6       8.4         5.6       0.1      21.7     2.0    7.1     0.6      8.5      2.3     18.5      39%          1110
6     VILL/R-P   7.27    1.57        4.3       7.2         7.5       0.4      19.3     3.2    7.5     0.8      7.4      1.1     16.9      45%          1216
7     MS/R-G     7.95    0.40        1.3       1.9         1.0       0.1       4.3     0.8    1.6     0.2      1.2      0.5      3.4      46%          265
8       TS/C     8.38    0.38        1.2       1.3         1.0       0.1       3.6     0.9    1.6     0.2      1.1      0.1      3.0      53%          265
9     BV/R-G     7.44    0.50       1.75       1.6         1.3       0.2       4.9     1.1    2.4     0.2      1.4      0.1      4.1      58%          369
10       MS/P     7.74    0.85        3.1       5.5         1.8       0.0      10.5     0.9    5.6     0.6      1.4      0.1      7.6      73%          899
1
Pounds of 100% sulfuric acid to inject per ac-ft of irrigation water.

SORT BY EC
EC        Ca        Mg        Na                  Sum            HCO3-   CO3-2   C1-1     SO 4-2    Sum      HCO3-         Reqd
Well        pH                                             K meq/l              SAR
dS/m      meq/l     meq/l     meq/l               Cations         meq/l   meq/l   meq/l    meq/l    Anions   (%Anion)       LF(%)
1      TS/R-Z     7.28      0.16      0.35      0.5       0.5     0.1       1.4       0.8      0.4       0.2       0.5    0.1      1.1      34%          1%
2       TS/C      8.38      0.38        1.2     1.3       1.0     0.1       3.6       0.9      1.6       0.2       1.1    0.1      3.0      53%          3%
3     MS/R-G      7.95      0.40        1.3     1.9       1.0     0.1       4.3       0.8      1.6       0.2       1.2    0.5      3.4      46%          4%
4     BV/R-G      7.44      0.50      1.75      1.6       1.3     0.2       4.9       1.1      2.4       0.2       1.4    0.1      4.1      58%          5%
5       MS/P      7.74      0.85        3.1     5.5       1.8     0.0      10.5       0.9      5.6       0.6       1.4    0.1      7.6      73%         13%
6     VILL/R-P    7.27      1.57        4.3     7.2       7.5     0.4      19.3       3.2      7.5       0.8       7.4    1.1     16.9      45%         35%
7     BAR/P-1     7.14      1.73        7.6     8.4       5.6     0.1      21.7       2.0      7.1       0.6       8.5    2.3     18.5      39%         41%
8     BAR/R-E     7.52      1.76        7.1     9.7       7.1     0.1      23.9       2.5      6.8       0.8       9.3    3.0     19.8      34%         42%
9     BAR/P-H     7.44      1.81        8.4     9.8       7.0     0.0      25.3       2.3      6.0       0.8       8.4    4.4     19.6      30%         44%
10     VILL/P-N    7.58      2.22        7.8     8.3       7.8     0.0      23.9       2.8      5.2       0.8      10.2    3.3     19.4      27%         62%
1
Required LEACHING FRACTION (LF) as a % of water in excess of crop ET to maintain an average rootzone saturation extract EC of 1.5 dS/m.           For
example: Water 5, MS/P EC=0.85 dS/m, LF = 13%. If walnut ET = 1100mm for the season, then APPLIED WATER = 1100 * 1.13 = 1243mm
1.5 dS/m is the current published salinity threshold for almonds, which is classed as a "Sensitive Crop" for almonds. We do not have a numeric
threshold for walnuts at this time.

```
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